In order to properly maintain the operation of a telephone system, it is desirable to monitor electrical characteristics, such as the loop resistance and DC balance, of the multi-wire subscriber line that connects customer-premises equipment to the telephone company central office switch.
Heretofore, these characteristics have been monitored by test equipment located at a central test site. The equipment requires service personnel at the customer premises, or some other location remote from the test site, in order to make connection, under direction from the test site, between the various leads that constitute the subscriber line and specified reference terminals, such as ground.
The subject invention mitigates these requirements by employing test apparatus to effectuate the necessary connections between the (T) and (R) leads at the customer premises under remote control from the test site.